diff --git a/compiler/heptagon/parsing/hept_lexer.mll b/compiler/heptagon/parsing/hept_lexer.mll
index e9891e6..629d426 100644
--- a/compiler/heptagon/parsing/hept_lexer.mll
+++ b/compiler/heptagon/parsing/hept_lexer.mll
@@ -57,6 +57,7 @@ List.iter (fun (str,tok) -> Hashtbl.add keyword_table str tok) [
  "whenot", WHENOT;
  "merge", MERGE;
  "on", ON;
+ "onot", ONOT;
  "map", MAP;
  "mapi", MAPI;
  "fold", FOLD;
diff --git a/compiler/heptagon/parsing/hept_parser.mly b/compiler/heptagon/parsing/hept_parser.mly
index c90ca7c..73a1a0e 100644
--- a/compiler/heptagon/parsing/hept_parser.mly
+++ b/compiler/heptagon/parsing/hept_parser.mly
@@ -39,7 +39,7 @@ open Hept_parsetree
 %token ASSUME
 %token ENFORCE
 %token WITH
-%token WHEN WHENOT MERGE ON
+%token WHEN WHENOT MERGE ON ONOT
 %token POWER
 %token LBRACKET LBRACKETGREATER
 %token RBRACKET LESSRBRACKET
@@ -285,8 +285,11 @@ ck:
 
 
 on_ck:
-  | c=constructor_or_bool LPAREN x=IDENT RPAREN             { Con(Cbase,c,x) }
-  | b=ck ON c=constructor_or_bool LPAREN x=IDENT RPAREN     { Con(b,c,x) }
+  | x=IDENT                                                { Con(Cbase,Q Initial.ptrue,x) }
+  | c=constructor_or_bool LPAREN x=IDENT RPAREN            { Con(Cbase,c,x) }
+  | b=ck ON x=IDENT                                        { Con(b,Q Initial.ptrue,x) }
+  | b=ck ONOT x=IDENT                                      { Con(b,Q Initial.pfalse,x) }
+  | b=ck ON c=constructor_or_bool LPAREN x=IDENT RPAREN    { Con(b,c,x) }
 
 
 equs:
diff --git a/test/good/auto.ept b/test/good/auto.ept
index 3d42889..ab579f4 100644
--- a/test/good/auto.ept
+++ b/test/good/auto.ept
@@ -3,14 +3,19 @@ let
   o = 0 fby (o + 1);
 tel
 
-node main() returns (c : bool)
+node f() returns(x,y : bool)
+let
+  (x,y) = (true,false)
+tel
+
+node main() returns (c,c1 : bool)
 let
   automaton
     state One
-      do c = true;
+      do (c,c1) = f()
       until count() = 5 then Two
     state Two
-      do c = false
+      do (c,c1) = f()
       until count() = 3 then One
   end
 tel